Riya's guess is 50,000 off, Dad's is 60,000 off — and her wider bullseye band seals the bonus too.
The hook
Everyone has an opinion about how many kilometers of blood vessels are packed into a human body, and everyone is wrong with total confidence. Estimation Nation weaponizes that: both players lock in a silent guess against a real, sourced number, closest one takes the point — and either player can call double-or-nothing right before the reveal, turning a trivia round into a genuine dare. It's Family Feud's "survey says" tension crossed with a bar bet, except the app already knows who's right and isn't afraid to say so.
A sample round
1 · The question drops for both players at once
2 · The dare: double-or-nothing before the reveal
3 · Exact match, double stakes — Dad's lead evaporates
How a round plays
- The app poses a real, sourced number question — nothing anyone already knows cold.
- Both players see it at once and lock in a silent estimate, with no peeking at the other screen.
- Closest guess to the true value takes the point — landing inside your own bullseye band (wider for less experienced guessers) scores a bonus on top.
- Before the reveal, either player can call double-or-nothing, turning the round into a high-stakes swing.
- First to the round target (say, 5 points) wins the estimation duel.
Why it's sticky
The fair-fight loop is baked into the scoring, not just the questions: everyone answers the exact same fact, but each player's bullseye band scales to their track record, so a 9-year-old's wild guess can out-bonus a parent's careful one. Layer on the double-or-nothing dare — a pure nerve check that turns "I think I'm right" into "I'm willing to bet on it" — and every round has two separate tensions: did I get it close, and did I get greedy. The facts themselves do the rest; "wait, actually?" is a hard feeling to walk away from.
Modes
- Duel — head-to-head, first to 5 points, double-or-nothing challenges available every round.
- Solo — race your personal best average error across a themed fact deck.
- Party relay — pass the phone; the whole group locks in silently, closest of the crowd scores, loudest reactions saved for the reveal.
Build notes
Size: M. The shared shell provides the split-screen duel frame, the adaptive-handicap module (bullseye tolerance bands per player), timers, scorebar, and reveal animation. The real work is game-specific: an estimation-facts dataset with sources baked in at build time, so every "true answer" is checkable and never goes stale, plus difficulty banding of facts by how wild the number is, and the double-or-nothing wager logic. Round logic lives in a plain JS module decoupled from rendering — a future async "challenge a friend by link" mode reuses the same estimate-and-reveal engine without a rewrite.